Multi-touch positioning method for capacitive touch panel

ABSTRACT

A multi-touch positioning method for a capacitive touch panel includes following steps. A candidate touching position array including a first and a second candidate position groups is generated when the capacitive touch panel is touched by two objects. The first and the second candidate position groups include two first and second candidate positions, respectively. Next, the signal magnitude sensed by a sensing element and respectively corresponding to the first and the second candidate position groups are compared. Then, when the signal magnitude corresponding to the first candidate position group is greater than that corresponding to the second candidate position group, one of the two first candidate positions closer to the sensing element along a first direction is determined as a first actual touching position, and one of the two second candidate positions farther from the sensing element along the first direction is determined as a second actual touching position.

This application claims the benefit of Taiwan application Serial No.97136534, filed Sept. 23, 2008, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a positioning method, and moreparticularly to a multi-touch positioning method for a capacitive touchpanel.

2. Description of the Related Art

Along with the development of technology, the application of touchpanels has become more and more popular. With the disposition of a touchpanel in an electronic product, a user can operate the electronicproduct through directly touching the touch panel. For the user, thedisposition of a touch panel in an electronic product improves theconvenience in operating the electronic product.

Referring to FIG. 1, touch positions sensed when two positions of aconventional capacitive touch panel are touched is shown. When a usertouches two positions A1 and A2 on the capacitive touch panel 100 at thesame time, the capacitive touch panel 100 determines that the touchedpositions could be positions A1, A2, B1 and B2 according to the positionfrom which the signals are obtained. However, the capacitive touch panel100 can not further determine that the actual touched positions are thepositions A1 and A2.

The operation of the capacitive touch panel is restricted and bringsinconvenience to the user. Thus, how to make the capacitive touch panelbe capable of recognizing multi-touch positions so as to improve theapplication of the capacitive touch panel has become the focus to themanufacturers.

SUMMARY OF THE INVENTION

The invention is directed to a multi-touch positioning method for acapacitive touch panel capable of determining several touched positionsof the capacitive touch panel, so that the application of the capacitivetouch panel is increased to facilitate the popularization of thecapacitive touch panel, and it is more convenient for a user tooperation the capacitive touch panel.

According to an embodiment of the present invention, a multi-touchpositioning method for a capacitive touch panel is provided. Thecapacitive touch panel has several first capacitive sensor pads arrangedin a matrix and several second capacitive sensor pads arranged in amatrix. The first capacitive sensor pads arranged in the same row alonga first direction are electrically connected to one another and coupledto a sensing element. The second capacitive sensor pads arranged in thesame row along a second direction are electrically connected to oneanother and coupled to the sensing element. One of the first capacitivesensor pads is adjacent to at least one of the second capacitive sensorpads. A position is defined by one of the first capacitive sensor padsand one of the second capacitive sensor pads which are adjacent to eachother. The method includes following steps. (a) A candidate touchingposition array is generated correspondingly when the capacitive touchpanel is touched by at least two objects, wherein the candidate touchingposition array includes a first candidate position group and a secondcandidate position group, the first candidate position group includes atleast two first candidate positions arranged along the first direction,and the second candidate position group includes at least two secondcandidate positions arranged along the first direction. (b1) The signalmagnitude which is sensed by the sensing element and corresponds to thefirst candidate position group is compared with the signal magnitudewhich is sensed by the sensing element and corresponds to the secondcandidate position group. (c1) When the signal magnitude correspondingto the first candidate position group is larger than the signalmagnitude corresponding to the second candidate position group, one ofthe two first candidate positions which is closer to the sensing elementalong the first direction is determined as a first actual touchingposition, and one of the two second candidate positions which is fartherfrom the sensing element along the first direction is determined as asecond actual touching position.

According to another embodiment of the present invention, a multi-touchpositioning method for a capacitive touch panel is provided. Thecapacitive touch panel has several first capacitive sensor pads arrangedin a matrix and several second capacitive sensor pads arranged in amatrix. The first capacitive sensor pads arranged in the same row alonga first direction are electrically connected to one another and coupledto a sensing element. The second capacitive sensor pads arranged in thesame row along a second direction are electrically connected to oneanother and coupled to the sensing element. One of the first capacitivesensor pads is adjacent to at least one of the second capacitive sensorpads. A position is defined by one of the first capacitive sensor padsand one of the second capacitive sensor pads which are adjacent to eachother. The method includes following steps. (a) A candidate touchingposition array is generated correspondingly when the capacitive touchpanel is touched by at least three objects, wherein the candidatetouching position array includes a first candidate position group, asecond candidate position group and a third candidate position group,the first candidate position group includes at least three firstcandidate positions arranged along the first direction, the secondcandidate position group includes at least three second candidatepositions arranged along the first direction, and the third candidateposition group includes at least three third candidate positionsarranged along the first direction. (b1) The signal magnitude which issensed by the sensing element and corresponds to the first candidateposition group, the signal magnitude which is sensed by the sensingelement and corresponds to the second candidate position group, and thesignal magnitude which is sensed by the sensing element and correspondsto the third candidate position group are compared. (c1) When the signalmagnitude corresponding to the first candidate position group is largerthan the signal magnitude corresponding to the second candidate positiongroup and the signal magnitude corresponding to the second candidateposition group is larger than the signal magnitude corresponding to thethird candidate position group, one of the three first candidatepositions which is closest to the sensing element along the firstdirection is determined as a first actual touching position, one of thethree second candidate positions which is located between the secondcandidate position closest to the sensing element and the secondcandidate position farthest from the sensing element along the firstdirection is determined as a second actual touching position, and one ofthe three third candidate positions which is farthest from the sensingelement along the first direction is determined as a third actualtouching position.

The invention will become apparent from the following detaileddescription of the preferred but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Related Art) shows touch positions sensed when two positions ofa conventional capacitive touch panel are touched;

FIG. 2 shows a flowchart of a multi-touch positioning method accordingto a first embodiment of the invention;

FIG. 3 shows an example of a capacitive touch panel used in thepositioning method according to the invention;

FIG. 4 shows an example of a candidate touching position array generatedin the step 701 in FIG. 2;

FIG. 5 shows a flowchart of verifying the results obtained in the step705 in FIG. 2;

FIG. 6 shows a flowchart of a multi-touch positioning method accordingto a second embodiment of the invention;

FIG. 7 shows an example of a candidate touching position array generatedin the step 801 in FIG. 6;

FIG. 8 shows a flowchart of verifying the results obtained in the step805 in FIG. 6;

FIG. 9 shows an example of a sectional view of the capacitive touchpanel in FIG. 3 along a cross-sectional line 9-9′;

FIG. 10 shows an example of a sensing circuit used by the sensingelement in FIG. 3; and

FIG. 11 shows another capacitive touch panel used for performing thepositioning method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a multi-touch positioning method for a capacitivetouch panel. The invention is exemplified by a first embodiment and asecond embodiment below. However, the first embodiment and the secondembodiment are for elaboration only not for limiting the scope of theinvention.

First Embodiment

Referring to FIG. 2 and FIG. 3, a flowchart of a multi-touch positioningmethod according to a first embodiment of the invention is shown in FIG.2, and an example of a capacitive touch panel used in the positioningmethod according to the invention is shown in FIG. 3. The positioningmethod is illustrated by being applied to the capacitive touch panel 200in FIG. 3.

In FIG. 3, the capacitive touch panel 200 has several first capacitivesensor pads 210 arranged in a matrix and several second capacitivesensor pads 220 arranged in a matrix. The first capacitive sensor pads210 arranged in the same row along a first direction D1 are electricallyconnected to one another and coupled to a sensing element 230. Thesecond capacitive sensor pads 220 arranged in the same row along asecond direction D2 are electrically connected to one another andcoupled to the sensing element 230. One of the first capacitive sensorpads 210 is adjacent to at least one of the second capacitive sensorpads 220. A position is defined by one of the first capacitive sensorpads 21 0 and one of the second capacitive sensor pads 220 which areadjacent to each other.

The positioning method in FIG. 2 includes following steps. Firstly, inthe step 701, when the capacitive touch panel 200 is touched by twoobjects (such as a user's fingers), a candidate touching position arrayas indicated in FIG. 4 is generated correspondingly. Referring to FIG.4, an example of a candidate touching position array generated in thestep 701 in FIG. 2 is shown. For simplification, the first capacitivesensor pads 210 and the second capacitive sensor pads 220 are notillustrated in FIG. 4. As shown in FIG. 4, the candidate touchingposition array includes a first candidate position group G1 and a secondcandidate position group G2. The first candidate position group G1includes two first candidate positions 301 and 303 arranged along thefirst direction D1, and the second candidate position group G2 includestwo second candidate positions 305 and 307 arranged along the firstdirection D1.

Next, in the step 703, the signal magnitude which is sensed by thesensing element 230 and corresponds to the first candidate positiongroup G1 is compared with the signal magnitude which is sensed by thesensing element 230 and corresponds to the second candidate positiongroup G2.

As the distance between the touched position and the sensing element isinversely correlated with the signal magnitude corresponding to thetouched position, actual touching positions are determined in the step705 according to the above relationship. In the step 705, when thesignal magnitude corresponding to the first candidate position group G1is larger than the signal magnitude corresponding to the secondcandidate position group G2, one of the two first candidate positions301 and 303 which is closer to the sensing element 230 along the firstdirection D1 is determined as a first actual touching position, and oneof the two second candidate positions 305 and 307 which is farther fromthe sensing element 230 along the first direction D1 is determined as asecond actual touching position. As indicated in FIG. 4, compared withthe first candidate position 303, the first candidate position 301 iscloser to the sensing element 230 along the first direction D1, andcompared with the second candidate position 307, the second candidateposition 305 is farther from the sensing element 230 along the firstdirection D1. Thus, in the present embodiment of the invention, thefirst candidate position 301 is the first actual touching position, andthe second candidate position 305 is the second actual touchingposition.

Thus, when two or even more positions on the capacitive touch panel aretouched by a user, the capacitive touch panel using the positioningmethod according to the present embodiment of the invention can sensethe touched positions, hence having a diversified range of application.

The positioning method according to the present embodiment of theinvention is further elaborated below. As indicated in FIG. 4, thecapacitive touch panel 200 has a first edge E1 and a second edge E2substantially perpendicular to the first edge E1. The first direction D1is substantially perpendicular to the second direction D2. The firstedge E1 is substantially perpendicular to the first direction D1. Thesecond edge E2 is substantially perpendicular to the second directionD2. For example, in the step 705, which one of the first candidatepositions 301 and 303 is closer to the sensing element 230 is determinedaccording to the distance between each of the first candidate positions301 and 303 and the first edge E1 in the first direction D1, and whichone of the second candidate positions 305 and 307 is closer to thesensing element 230 is determined according to the distance between eachof the second candidate positions 305 and 307 and the first edge E1 inthe first direction D1.

According to the positioning method in FIG. 2, the signal magnitudescorresponding to the first candidate position group G1 and the secondcandidate position group G2 of the candidate touching position array arecompared so as to determine the actual touching positions. However,anyone who is skilled in the related art of the invention willunderstand that according to the positioning method in FIG. 2, thesignal magnitudes corresponding to a third candidate position group G3and a fourth candidate position group G4 of the candidate touchingposition array can also be compared so as to determine the actualtouching positions. Besides, the results obtained in the step 705 inFIG. 2 can also be verified by the signal magnitudes corresponding tothe third candidate position group G3 and the fourth candidate positiongroup G4. The positions of the third candidate position group G3 and thefourth candidate position group G4 are indicated in FIG. 4. The thirdcandidate position group G3 includes two third candidate positionsarranged along the second direction D2. The two third candidatepositions include the first candidate position 303 and the secondcandidate position 305. The fourth candidate position group G4 includestwo fourth candidate positions arranged along the second direction D2.The two fourth candidate positions include the other first candidateposition 301 and the other second candidate position 307.

The process of verifying the results obtained in the step 705 in FIG. 2is shown in FIG. 5. However, the positioning method according to thepresent embodiment of the invention does not have to execute the stepsin FIG. 5. In the step 707 in FIG. 5, the signal magnitude which issensed by the sensing element 230 and corresponds to the third candidateposition group G3 is compared with the signal magnitude which is sensedby the sensing element 230 and corresponds to the fourth candidateposition group G4.

In the step 709, when the signal magnitude corresponding to the thirdcandidate position group G3 is larger than the signal magnitudecorresponding to the fourth candidate position group G4, one of the twothird candidate positions (that is, the candidate position numbered with305) which is closer to the sensing element 230 along the seconddirection D2 is determined as one of the first actual touching positionand the second actual touching position, and one of the two fourthcandidate position (that is, the candidate position numbered with 301)which is farther from the sensing element 230 along the second directionD2 is determined as the other one of the first actual touching positionand the second actual touching position so as to reconfirm the resultsobtained in the step 705 in FIG. 2.

In the step 709, which one of the third candidate positions is closer tothe sensing element 230 is determined according to the distance betweeneach of the third candidate positions and the second edge E2 in thesecond direction D2, and which one of the fourth candidate positions iscloser to the sensing element 230 is determined according to thedistance between each of the fourth candidate positions and the secondedge E2 in the second direction D2, for example.

Referring to FIG. 9, an example of a sectional view of the capacitivetouch panel in FIG. 3 along a cross-sectional line 9-9′ is shown. Thefirst capacitive sensor pad 210 and the second capacitive sensor pad 220are disposed between two substrates 902 and 904. The two substrates 902and 904 are exemplified by glass substrates. When the capacitive touchpanel 200 is touched by a finger 906, the equivalent capacitance betweenthe first capacitive sensor pad 210 and its adjacent second capacitivesensor pads 220 will be changed. A difference is between the equivalentcapacitance before and after the capacitive touch panel 200 is touched.The signal magnitude of the signal received by the sensing element 230will reflect the difference to be used as a basis for determiningwhether the capacitive touch panel 200 is touched.

Referring to FIG. 10, an example of a sensing circuit 1002 used by thesensing element 230 in FIG. 3 is shown. Let the second capacitive sensorpads 220 arranged in the first row in FIG. 3 be taken as an example. Thesecond capacitive sensor pads 220 arranged in the first row areelectrically connected to the sensing element 230 through a sensing wire250. Suppose the equivalent capacitor corresponding to all of the secondcapacitive sensor pads 220 arranged in the first row is CG before thecapacitive touch panel is touched by a finger, and the equivalentcapacitor corresponding to all of the second capacitive sensor pads 220arranged in the first row is C1 and Cx coupled in parallel after thecapacitive touch panel is touched by a finger. The sensing circuit 1002includes switches SW1˜SW3, a capacitor C2, a resistor R, a comparator1004, a latch 1006, and a counter 1008. The periods that the switchesSW1 and SW2 are turned on are not overlapped. When the switch SW1 isturned on, the capacitors C1 and Cx are charged. Afterwards, the switchSW2 is turned on, the capacitors C1 and Cx will charge the capacitor C2.When the terminal voltage Vcm of the capacitor C2 is larger than thereference voltage Vref, the output voltage Vd of the comparator 1004 isa positive voltage. When the clock signal CK is changed to be at highlevel, the latch 1006 samples the output voltage Vd and correspondinglyoutputs the voltage Vo. When the sampled output voltage Vd is a positivevoltage, the voltage Vo is at high level and maintains for a clockperiod with one clock signal CK. In addition, when Vcm is larger thanthe reference voltage Vref, the switch SW3 is turned on, so that thecapacitor C2 is discharged through the resistor R, or the switch SW3will not be turned on. The counter 1008 counts the number of clockperiods when the voltage Vo is at high level and outputs a count Cnt. Asthe sensing element 230 scans the second capacitive sensor pads row byrow, the count Cnt preferably is a count generated within a sensingperiod when the second capacitive sensor pads arranged in one row aresensed. The value of the capacitor Cx is obtained according to the valueof the count Cnt. The signal magnitude is correlated with the count Cnt.For example, the larger the count Cnt, the larger the signal magnitude.

The counter 1008 can be implemented by way of hardware or software.

However, the invention can also calculate the value of the capacitor Cxwith other sensing circuits as long as any parameter of an electricalsignal outputted by the sensing circuit is correlated with the capacitorCx. For example, the capacitor Cx or the combination of the capacitorsCx and C1 which is correlated with the output voltage, the outputfrequency, or the output power of the sensing circuit can be applied tothe invention.

In addition, one of the reasons why the distance between the touchedposition and the sensing element 230 is inversely correlated with thesignal magnitude corresponding to the touched position is that when thetouched position is far away from the sensing element 230, thetransmission path for the signal to be transmitted to the sensingelement 230 is longer and the equivalent resistance of the transmissionpath when the signal is transmitted is larger, so the signal magnitudewill be diminished. In order to let the sensing element 230 have bettersensing effect, the difference between the signal magnitudes generatedwhen different positions are touched can be increased by changing theequivalent resistance corresponding to the different positions.

As shown in FIG. 3, in the step 701, the sensing element 230 senses thesignal corresponding to the first candidate position group G1 throughthe first capacitive sensor pads 210 and connectors 240 arranged in thesame row of the capacitive touch panel 200. The connectors 240 areconnected between two adjacent first capacitive sensor pads 210. Inorder to increase the difference between the signal magnitudescorresponding to different positions for precisely determining thetouched position, the resistances of the first capacitive sensor pads210 and the connectors 240 at different positions are different.Therefore, the difference between the signal magnitudes corresponding todifferent positions is increased to facilitate the determination of thesensing element 230.

For example, of the first capacitive sensor pads 210 and/or theconnectors 240 arranged in the same row along the first direction D1,the resistances of the first capacitive sensor pads 210 and theconnectors 240 which is closer to the sensing element 230 is smallerthan that farther from the sensing element 230. Thus, along the firstdirection D1, the difference between the signal magnitude correspondingto the first capacitive sensor pad closer to the sensing element 230 andthe signal magnitude corresponding to the first capacitive sensor padfarther from the sensing element 230 is even increased. The resistanceof the first capacitive sensor pad can be adjusted by changing at leastone of the area and the thickness of the first capacitive sensor pad.The resistance of the connector 240 can be adjusted by changing the areaof the cross section of the connector 240 (for example, the width of theconnector 240). Furthermore, the resistance of the second capacitivesensor pad can also be changed in the same way so as to increase theaccuracy in determination.

The shape of the pad used in the capacitive touch panel of the presentembodiment of the invention is not limited to a quadrangle as shown inFIG. 3. Other shapes such as a hexagon, a triangle, or an octagon canalso be used as the shape of the pad used in the capacitive touch panel.Referring to FIG. 11, another capacitive touch panel used for performingthe positioning method according to the invention is shown. The firstcapacitive sensor pads can be loop-shaped such as pads 210′ in FIG. 11,and the second capacitive sensor pads can be pads 220′ disposed in theloop-shaped pads 210′. Besides, the second capacitive sensor pads canalso be loop-shaped pads, and the first capacitive sensor pads can alsobe pads disposed in the loop-shaped pads.

The positioning method of the present embodiment is for determiningmulti-touch positions of the capacitive touch panel. The positioningmethod determines the actual touching positions according to the signalmagnitudes of several candidate position groups as well as the distancesbetween each of the candidate positions of the candidate position groupsand the sensing element. Thus, the positioning method of the presentembodiment can determine several actual touching positions withoutadjusting or changing the components of the capacitive touch panel, sothat the application of the capacitive touch panel using the positioningmethod of the present embodiment is even diversified.

Second Embodiment

The positioning method of the present embodiment differs from thepositioning method of the first embodiment in the determined number oftouched positions of the capacitive touch panel. Referring to FIG. 6, aflowchart of a multi-touch positioning method according to a secondembodiment of the invention is shown. The present embodiment of theinvention is exemplified by applying the positioning method to thecapacitive touch panel 200 in FIG. 3. However, the application of thepositioning method of the present embodiment is not limited to thecapacitive touch panel 200.

The steps 801 and 803 in FIG. 6 are different from the steps 701 and 703in FIG. 2 in the number of touched positions, and the similarities arenot repeated here. Referring to FIG. 7, an example of a candidatetouching position array generated in the step 801 in FIG. 6 is shown.For simplification, the first capacitive sensor pads 210 and the secondcapacitive sensor pads 220 of the capacitive touch panel 200 are notillustrated in FIG. 7. In the step 803, the signal magnitudes of thefirst candidate position group G1′, the second candidate position groupG2′ and the third candidate position group G3′ of the candidate touchingposition array sensed by the sensing element 230 and respectivelycorrespond to the first candidate position group G1′, the secondcandidate position group G2′ and the third candidate position group G3′are compared.

Then, the step 805 is executed after the step 803. In the step 805, whenthe signal magnitude corresponding to the first candidate position groupG1′ is larger than the signal magnitude corresponding to the secondcandidate position group G2′ and the signal magnitude corresponding tothe second candidate position group G2′ is larger than the signalmagnitude corresponding to the third candidate position group G3′, oneof the three first candidate positions 501, 503 and 505 closest to thesensing element 230 along the first direction D1 is determined as afirst actual touching position, one of the three second candidatepositions 507, 509 and 511 along the first direction D1 located betweenthe second candidate position closest to the sensing element 230 and thesecond candidate position farthest from the sensing element 230 isdetermined as a second actual touching position, and one of the threethird candidate positions 513, 515 and 517 farthest from the sensingelement 230 along the first direction D1 is determined as a third actualtouching position. As indicated in FIG. 7, compared with the firstcandidate positions 503 and 505, the first candidate position 501 isclosest to the sensing element 230 along the first direction D1.Compared with the second candidate positions 507 and 511, the secondcandidate position 509 is located between the second candidate position(the second candidate position 507) closest to the sensing element 230and the second candidate position (the second candidate position 511)farthest from the sensing element 230 along the first direction D1.Compared with the third candidate positions 513 and 515, the thirdcandidate position 517 is farthest from the sensing element 230 alongthe first direction D1. Thus, the first candidate position 501 is thefirst actual touching position, the second candidate position 509 is thesecond actual touching position, and the third candidate position 517 isthe third actual touching position.

In the step 805 of the present embodiment, according to the distancebetween each of the first candidate positions and the first edge E1 inthe first direction D1, which one of the first candidate positions iscloser to or farther from the sensing element 230 or is located betweenthe first candidate position closest to the sensing element 230 and thefirst candidate position farthest from the sensing element 230 isdetermined. According to the distance between each of the secondcandidate positions and the first edge E1 in the first direction D1,which one of the second candidate positions is closer to or farther fromthe sensing element 230 or is located between the second candidateposition closest to the sensing element 230 and the second candidateposition farthest from the sensing element 230 is determined. Accordingto the distance between each of the third candidate positions and thefirst edge E1 in the first direction D1, which one of the thirdcandidate positions is closer to or farther from the sensing element 230or is located between the third candidate position closest to thesensing element 230 and the third candidate position farthest from thesensing element 230 is determined.

Furthermore, the results obtained according to the positioning method ofthe present embodiment in FIG. 6 can be verified by the signalmagnitudes of the fourth candidate position group G4′, the fifthcandidate position group G5′ and the sixth candidate position group G6′in FIG. 7. The fourth candidate position group G4′, the fifth candidateposition group G5′ and the sixth candidate position group G6′ areindicated in FIG. 7. The fourth candidate position group G4′ includesthree fourth candidate positions arranged in the same row along thesecond direction D2. The three fourth candidate positions include onefirst candidate position 505, one second candidate position 511 and onethird candidate position 517. The fifth candidate position group G5′includes three fifth candidate positions arranged in the same row alongthe second direction D2. The three fifth candidate positions includeanother first candidate position 503, another second candidate position509 and another third candidate position 515. The sixth candidateposition group G6′ includes three sixth candidate positions arranged inthe same row along the second direction D2. The three sixth candidatepositions includes the other first candidate position 501, the othersecond candidate position 507 and the other third candidate position513. The first direction D1 is, for example, substantially perpendicularto the second direction D2.

The results obtained in the step 805 in FIG. 6 are further verified bythe steps shown in FIG. 8. However, the positioning method of thepresent embodiment of the invention does not have to execute the stepsin FIG. 8. In the step 807 in FIG. 8, the signal magnitudes sensed bythe sensing element 230 and respectively correspond to the fourthcandidate position group G4′, the fifth candidate position group G5′,and the sixth candidate position group G6′ are compared.

In the step 809, when the signal magnitude corresponding to the fourthcandidate position group G4′ is larger than the signal magnitudecorresponding to the fifth candidate position group G5′ and the signalmagnitude corresponding to the fifth candidate position group G5′ islarger than the signal magnitude corresponding to the sixth candidateposition group G6′, one of the three fourth candidate positions (thatis, the candidate position numbered with 517) closest to the sensingelement 230 along the second direction D2 is determined as one of thefirst actual touching position, the second actual touching position andthe third actual touching position. Besides, one of the three fifthcandidate positions located between the fifth candidate position closestto the sensing element 230 and the fifth candidate position farthestfrom the sensing element 230 along the second direction D2 (that is, thecandidate position numbered with 509) is determined as another one ofthe first actual touching position, the second actual touching positionand the third actual touching position. Furthermore, one of the threesixth candidate positions along the second direction D2 farthest fromthe sensing element 230 (that is, the candidate position numbered with501) is determined as the other one of the first actual touchingposition, the second actual touching position and the third actualtouching position. Therefore, the results obtained in the step 805 inFIG. 6 are reconfirmed.

In the step 809, according to the distance between each of the fourthcandidate positions and the second edge E2 in the second direction D2,which one of the fourth candidate positions is closer to or farther fromthe sensing element 230 or is located between the fourth candidateposition closest to the sensing element 230 and the fourth candidateposition farthest from the sensing element 230 is determined. Accordingto the distance between each of the fifth candidate positions and thesecond edge E2 in the second direction D2, which one of the fifthcandidate positions is closer to or farther from the sensing element 230or is located between the fifth candidate position closest to thesensing element 230 and the fifth candidate position farthest from thesensing element 230 is determined. According to the distance betweeneach of the sixth candidate positions and the second edge E2 in thesecond direction D2, which one of the sixth candidate positions iscloser to or farther from the sensing element 230 or is located betweenthe sixth candidate position closest to the sensing element 230 and thesixth candidate position farthest from the sensing element 230 isdetermined.

According to the multi-touch positioning method for the capacitive touchpanel disclosed in the above embodiments of the invention, the signalmagnitudes of several candidate position groups and the distancesbetween each of the candidate positions of the candidate position groupsand the sensing element are used as a basis for determining actualtouching positions. Thus, the positioning method of the embodiments doesnot need to change the components of the capacitive touch panel, so thatthe application of the capacitive touch panel is even diversifiedwithout incurring extra cost.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A multi-touch positioning method for a capacitive touch panel,wherein the capacitive touch panel has a plurality of first capacitivesensor pads arranged in a matrix and a plurality of second capacitivesensor pads arranged in a matrix, the first capacitive sensor padsarranged in the same row along a first direction are electricallyconnected to one another and coupled to a sensing element, the secondcapacitive sensor pads arranged in the same row along a second directionare electrically connected to one another and coupled to the sensingelement, one of the first capacitive sensor pads is adjacent to at leastone of the second capacitive sensor pads, a position is defined by oneof the first capacitive sensor pads and one of the second capacitivesensor pads which are adjacent to each other, and the method comprises:(a) generating a candidate touching position array correspondingly whenthe capacitive touch panel is touched by at least two objects, whereinthe candidate touching position array comprises a first candidateposition group and a second candidate position group, the firstcandidate position group comprises at least two first candidatepositions arranged along the first direction, and the second candidateposition group comprises at least two second candidate positionsarranged along the first direction; (b1) comparing the signal magnitudewhich is sensed by the sensing element and corresponds to the firstcandidate position group with the signal magnitude which is sensed bythe sensing element and corresponds to the second candidate positiongroup; and (c1) determining one of the two first candidate positionswhich is closer to the sensing element along the first direction as afirst actual touching position and determining one of the two secondcandidate positions which is farther from the sensing element along thefirst direction as a second actual touching position when the signalmagnitude corresponding to the first candidate position group is largerthan the signal magnitude corresponding to the second candidate positiongroup.
 2. The positioning method according to claim 1, wherein in thestep (a), the candidate touching position array further comprises athird candidate position group and a fourth candidate position group,the third candidate position group comprises at least two thirdcandidate positions arranged along the second direction, the at leasttwo third candidate positions comprise one of the first candidatepositions and one of the second candidate positions, the fourthcandidate position group comprises at least two fourth candidatepositions arranged along the second direction, the at least two fourthcandidate positions comprise the other first candidate position and theother second candidate position, the first direction is substantiallyperpendicular to the second direction, and after the step (a), themethod further comprises: (b2) comparing the signal magnitude which issensed by the sensing element and corresponds to the third candidateposition group with the signal magnitude which is sensed by the sensingelement and corresponds to the fourth candidate position group; and (c2)determining one of the two third candidate positions which is closer tothe sensing element along the second direction as one of the firstactual touching position and the second actual touching position anddetermining one of the two fourth candidate positions which is fartherfrom the sensing element along the second direction as the other one ofthe first actual touching position and the second actual touchingposition when the signal magnitude corresponding to the third candidateposition group is larger than the signal magnitude corresponding to thefourth candidate position group, so as to reconfirm the results obtainedin the step (c1).
 3. The positioning method according to claim 1,wherein in the step (a), the sensing element senses the signalcorresponding to the first candidate position group through the firstcapacitive sensor pads arranged in the same row; wherein of the firstcapacitive sensor pads arranged in the same row along the firstdirection, the equivalent resistance of the first capacitive sensor padcloser to the sensing element is smaller than the equivalent resistanceof the first capacitive sensor pad farther from the sensing element. 4.The positioning method according to claim 1, wherein the capacitivetouch panel further has a plurality of connectors connected between twoadjacent first capacitive sensor pads, in the step (a), the sensingelement senses the signal corresponding to the first candidate positiongroup through the first capacitive sensor pads and the connectorsarranged in the same row; wherein of the connectors arranged in the samerow along the first direction, the equivalent resistance of theconnector closer to the sensing element is smaller than the equivalentresistance of the connector farther from the sensing element.
 5. Thepositioning method according to claim 1, wherein the capacitive touchpanel has a first edge and a second edge substantially perpendicular tothe first edge, the first edge is substantially perpendicular to thefirst direction, the second edge is substantially perpendicular to thesecond direction, in the step (c1), the distance between each of the twofirst candidate positions and the sensing element is determinedaccording to the distance between each of the two first candidatepositions and the first edge in the first direction, and the distancebetween each of the two second candidate positions and the sensingelement is determined according to the distance between each of the twosecond candidate positions and the first edge in the first direction. 6.A multi-touch positioning method for a capacitive touch panel, whereinthe capacitive touch panel has a plurality of first capacitive sensorpads arranged in a matrix and a plurality of second capacitive sensorpads arranged in a matrix, the first capacitive sensor pads arranged inthe same row along a first direction are electrically connected to oneanother and coupled to a sensing element, the second capacitive sensorpads arranged in the same row along a second direction are electricallyconnected to one another and coupled to the sensing element, one of thefirst capacitive sensor pads is adjacent to at least one of the secondcapacitive sensor pads, a position is defined by one of the firstcapacitive sensor pads and one of the second capacitive sensor padswhich are adjacent to each other, and the method comprises: (a)generating a candidate touching position array correspondingly when thecapacitive touch panel is touched by at least three objects, wherein thecandidate touching position array comprises a first candidate positiongroup, a second candidate position group and a third candidate positiongroup, the first candidate position group comprises at least three firstcandidate positions arranged along the first direction, the secondcandidate position group comprises at least three second candidatepositions arranged along the first direction, and the third candidateposition group comprises at least three third candidate positionsarranged along the first direction; (b1) comparing the signal magnitudewhich is sensed by the sensing element and corresponds to the firstcandidate position group, the signal magnitude which is sensed by thesensing element and corresponds to the second candidate position groupand the signal magnitude which is sensed by the sensing element andcorresponds to the third candidate position group; and (c1) determiningone of the three first candidate positions which is closest to thesensing element along the first direction as a first actual touchingposition, determining one of the three second candidate positions whichis located between the second candidate position closest to the sensingelement and the second candidate position farthest from the sensingelement along the first direction as a second actual touching position,and determining one of the three third candidate positions which isfarthest from the sensing element along the first direction as a thirdactual touching position when the signal magnitude corresponding to thefirst candidate position group is larger than the signal magnitudecorresponding to the second candidate position group and the signalmagnitude corresponding to the second candidate position group is largerthan the signal magnitude corresponding to the third candidate positiongroup.
 7. The positioning method according to claim 6, wherein in thestep (a), the candidate touching position array further comprises afourth candidate position group, a fifth candidate position group and asixth candidate position group, the fourth candidate position groupcomprises at least three fourth candidate positions arranged along thesecond direction, the at least three fourth candidate positions compriseone of the first candidate positions, one of the second candidatepositions and one of the third candidate positions, the fifth candidateposition group comprises at least three fifth candidate positionsarranged along the second direction, the at least three fifth candidatepositions comprise another first candidate position, another secondcandidate position and another third candidate position, the sixthcandidate position group comprises at least three sixth candidatepositions along the second direction, the at least three sixth candidatepositions comprise the other first candidate position, the other secondcandidate position and the other third candidate position, the firstdirection is substantially perpendicular to the second direction, andafter the step (a), the method further comprises: (b2) comparing thesignal magnitude which is sensed by the sensing element and correspondsto the fourth candidate position group, the signal magnitude which issensed by the sensing element and corresponds to the fifth candidateposition group, and the signal magnitude which is sensed by the sensingelement and corresponds to the sixth candidate position group; and (c2)determining one of the three fourth candidate positions which is closestto the sensing element along the second direction as one of the firstactual touching position, the second actual touching position and thethird actual touching position, determining one of the three fifthcandidate positions which is located between the fourth candidateposition closest to the sensing element and the fourth candidateposition farthest from the sensing element along the second direction asanother one of the first actual touching position, the second actualtouching position and the third actual touching position, anddetermining one of the three sixth candidate positions which is farthestfrom the sensing element along the second direction as the other one ofthe first actual touching position, the second actual touching positionand the third actual touching position when the signal magnitudecorresponding to the fourth candidate position group is larger than thesignal magnitude corresponding to the fifth candidate position group andthe signal magnitude corresponding to the fifth candidate position groupis larger than the signal magnitude corresponding to the sixth candidateposition group, so as to reconfirm the results obtained in the step(c1).
 8. The positioning method according to claim 6, wherein in thestep (a), the sensing element senses the signal corresponding to thefirst candidate position group through the first capacitive sensor padsarranged in the same row; wherein of the first capacitive sensor padsarranged in the same row along the first direction, the equivalentresistance of the first capacitive sensor pad closer to the sensingelement is smaller than the equivalent resistance of the firstcapacitive sensor pad farther from the sensing element.
 9. Thepositioning method according to claim 6, wherein the capacitive touchpanel further has a plurality of connectors connected between twoadjacent first capacitive sensor pads, in the step (a), the sensingelement senses the signal corresponding to the first candidate positiongroup through the first capacitive sensor pads and the connectorsarranged in the same row; wherein of the connectors arranged in the samerow along the first direction, the equivalent resistance of theconnector closer to the sensing element is smaller than the equivalentresistance of the connector farther from the sensing element.
 10. Thepositioning method according to claim 6, wherein the capacitive touchpanel has a first edge and a second edge substantially perpendicular tothe first edge, the first edge is substantially perpendicular to thefirst direction, the second edge is substantially perpendicular to thesecond direction, in the step (c1), the distance between each of thethree first candidate positions and the sensing element is determinedaccording to the distance between each of the three first candidatepositions and the first edge in the first direction, the distancebetween each of the three second candidate positions and the sensingelement is determined according to the distance between each of thethree second candidate positions and the first edge in the firstdirection, and the distance between each of the three third candidatepositions and the sensing element is determined according to thedistance between each of the three third candidate positions and thefirst edge in the first direction.